Scorpionfish adjust skin pattern contrast on different backgrounds.

The two scorpionfish species and are well camouflaged ambush predators that rapidly change body colouration to adjust to background colour in less than 1 min. We tested whether individuals of both species also adjust body pattern to that of the background. We placed fish on backgrounds of different pattern granularity and quantified the change in fish body pattern over 1 min.

Scorpionfish rapidly change colour in response to their background.

Background: To facilitate background matching in heterogenous environments, some animals rapidly change body colouration. Marine predatory fishes might use this ability to hide from predators and prey. Here, we focus on scorpionfishes (Scorpaenidae), well-camouflaged, bottom-dwelling sit-and-wait predators.

Body coloration as a dynamic signal during intrasexual communication in a cichlid fish.

Background: Intrasexual competition over access to resources can lead to aggression between individuals. Because overt aggression, i.e.

Same or different? Abstract relational concept use in juvenile bamboo sharks and Malawi cichlids.

Sorting objects and events into categories and concepts is an important cognitive prerequisite that spares an individual the learning of every object or situation encountered in its daily life. Accordingly, specific items are classified in general groups that allow fast responses to novel situations. The present study assessed whether bamboo sharks and Malawi cichlids can distinguish sets of stimuli (each stimulus consisting of two abstract, geometric objects) that meet two conceptual preconditions, i.